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C. L. Smith (219.) i^i 19;^7 reported that a spray of derris powder 
(U percent of rot men e) 2 pounds per 100 gallons of water, plus 2,5 pounds 
of coconut-oil soap (anhydrous basis) reduced the larval population of the 
Mexican bean beetle 90 percent and the adult population 9U percent at the 
end of 2U hours?. McCormick' s 0.75-P<^rcent-rotenone dust caused a larval 
reduction of 97 pf-rcent and an adult reduction of 83 percent. 
The United States Departniv-nt of Agriculture (W^) ir. 1937 released 
infor^'ation concerni:.g the work of the Bur'^au of Entomology and Plant 
Quarantine. The problem of the practical control of the Mexican bean 
beetle was advanced by a demonstration that sonie of the nevf insecticides 
containing rotenone are taken up by the bean -olant and distributed to the 
leaves in a way that ensures protection against the beetles for 10 days 
or longer, cutting down the ni^Jtibcr of applicrtions needed. 
The United States Bureau of Sntomolog.v and Plant Quarantine in 
a picture sheet in June 1937 recommended 3 pounds of finely ground derris 
or cube (rotenone, U percent) to 100 gallons of water as a spray or a. 
dust containing 0.5 P'^rcent of rotenone for the control of the Mexican 
bean beetle. Suitable diluents ar^- ta.lc, clay, sulfur, tobacco, gypsum, 
or other powders, except lime. Spraying has given better results than 
dusting. The nidor sides of the leaves should be thoroughly covered. 
The first application of insecticide (spray or dust) should be made 
when the beetles- are found in the field or when eggs become numerous 
on the under sides of the leaves. Repeat every week or 10 days if the 
insects are nuiir^rous. 
The Bureau of Entomology and Plnnt 0:uarantine (J9|*)in 1937 reported 
that sprays or dusts of cube or derris control the Mexican bean beetle at 
a minimum cost. 
Ultrawet added to cube dusts (0.75 percent of rotenone) and sprays 
(3 pounds per 100 gallons of water) did not improve their control of the 
Mexican bean beetle. — Walker (U06) in 1938. 
White in I936 ( U13 ) and I937 (UlU) recommended derris or cube sprnyg 
or dusts for the control of the Mexic-^n bean beetle. The spray should 
contain about 0.015 percent of rotenone(3 pounds of powder containing 
U percent of rotenone per 100 gallons of water) and the dust 0.5 percent 
of rotenone. Sprays are recommended in preference to dusts br cause they 
give better control and longer protection. No spreader or sticker is 
necessary with derris or cubf in water for use on beans. 
Brannon (^,|f]£) in I938 rer»ortr-d the results of an emoriment 
conducted at ITorfolk, Va4, against Mexican bean beetles on the spring 
crop of snap beans, to determine the relative effectiveness of derris, 
cube, and cryolite dusts and sprays. Based on the degree of foliage 
in.iury, derris and cube sprays containing 0.015 percent of rotenone and 
dust mixtures containing 0.5 percent of rotenone are the most effective 
materials yet devised for the control of the Mexican bean beetle. Ihist 
mixtures containir.g combinations of derris, pyrethrum, and sulfur were 
eoually as effective as dcrris-talc or cube- talc dust mixtures contain- 
ing the same percentage of rotonone. In December 193^ ^^ reported that 
tests made at Norfolk demonstrated that dusts or sprays containing derris, 
